Effect of superheat on the solidification structures of AISI 310S austenitic stainless steel

An experimental study was carried out to investigate the evolution of macrostructure and microstructure in AISI 310S stainless steel during solidification. Experimental findings suggested that the macrostructure and the microstructure of the cast material responded differently to variations in casting temperature. As the casting temperature decreased, the macro structure was refined, as expected, but the microstructure coarsened. A relationship was established between the proportion of equiaxed zone and superheat as follows: pct equiaxed zone =a +b ln (1/ΔT) wherea andb are constants. The relationship between grain width and superheat could be expressed by the equation $$gw = e^{left( {c + d/Delta T} right)} $$ wherec andd are constants determined by the distance from the edge of the ingot. The relationship between primary arm spacing and superheat could be expressed by the equation $$lambda _1 = p + q ln left( {1/Delta T} right)$$ wherep andq are constants determined by the distance from the edge of the ingot. The parameter “grain width ratio” has been introduced to describe the relationship between the shape and the nucleation and growth kinetics of the columnar grains.